STAT3 and cancer: The JAK dimers mediate phosphorylation of tyrosine 705 of STAT3, and the activated STAT3 is released from the kinase complex and subsequently translocates into the nucleus.441 As a transcriptional factor, nuclear STAT3 regulates the gene expression of a wide range of genes that are involved in promoting cancer cell growth, tumor invasion, and chemoresistance.442,443 The STAT3 pathway is significantly involved in the tumor progression and metastasis of GC.